Behavioral and electrophysiological measures of withdrawal hyperexcitability will be used to study the rapid development of physical dependence on alcohol in neural systems concerned with emotional expression in cats, monkeys and baboons. Efforts will focus on changes in excitability on the ventromedial area of the hypothalamus following varied blood alcohol levels and durations of exposure to alcohol in alert and otherwise undrugged preparations. Special attention will be paid to behaviorally facilitating pathways entering the VM area from the corticomedial amygdala and from the septum. These pathways appear to be similar in function but different in terms of their response to alcohol treatment. For purposes of comparison, studies will be made of changes in excitability of convergent pathways in the trigeminal motor system and of changes in response characteristics of long fiber bundles associated with the expression of emotional behavior. It is anticipated that this work will have significance for understanding some of the effects of alcohol on the CNS which may be important for the rapid development of physical dependence and, possibly, associated cyclic drinking patterns.